Dynamic dropdown list based on database

[Winnetou]

Hi all. I have a sheet with selection options in database format:

Tag	Value
A	123
A	234
A	321
B	12
B	34
C	1

On a second sheet I want the cells to have a dropdown list based on the filtered value of the database. The value which should be filtered on is in the header row, e.g.:

A	C	B
dropdown: 123, 234, 321	dropdown: 1	dropdown: 12, 34
dropdown: 123, 234, 321	dropdown: 1	dropdown: 12, 34

I can get the values from the database using the formula below, but that doesn't work for dropdown lists as it returns a matrix:
=UNIQUE(FILTER(Table1[Tag]; Table1[Tag]=A$1))

I would like to have it flexible (refererring to the header row) so that the order of the columns can be changed afterwards. Does anyone know how to achieve this?

 

[SunnyAlv]

Like this ?

Cell E2

=TEXTJOIN(", ",,UNIQUE(FILTER(Table1[Value],Table1[Tag]=E1,"")))

 

[jkpieterse]

Perhaps something along the lines of this: DependentValidation

 

[Winnetou]

Perhaps something along the lines of this: DependentValidation

Great, thanks! This was the solution:

=INDEX(Sheet2!$A$2:$C$2,MATCH(A1,Sheet2!A$1#,0))#